1. Field of the Invention
The present invention relates to a glass substrate for an optical disk or the like that is used for storing digital data, such as audio and video computer data, and graphics data. The present invention particularly relates to a method for manufacturing the glass substrate and facilitating the formation of track patterns in the surface thereof.
2. Description of the Related Art
Optical disks and other disks have been conventionally formed of polycarbonate, acrylic, epoxy, olefin, and other resinous materials. However, such materials are affected by high temperatures and humidity, and they tend to change adversely over time. Disks formed of these materials also are limited in their storage capacity. Accordingly, glass, which is not affected by temperature in this way, has been introduced as a material for forming optical disks and the like.
In manufacturing disks with glass, a glass plate is molded using a fusion method or a float method. The glass plate is cut into a desired shape and annealed. The preformed glass plate is press-molded using a mold having a surface that has been formed with great precision. Next, the plate undergoes such processes as polishing and surface treatments. Subsequently, a laser process is conducted to form tracks (grooves) in the surface of the disk, completing the process of manufacturing a glass substrate for an optical disk.
As described above, tracks are formed in the surface of the glass substrate by performing a laser process thereon. Accordingly, expensive equipment is necessary to perform this process, thereby increasing production costs.
In view of the foregoing, one object of the present invention is to provide an easy and inexpensive method for manufacturing a glass substrate and forming track patterns in the surface thereof. This object and others will be attained by a method of manufacturing a glass substrate for an optical disk, the method comprising the steps of preparing a press-mold formed of a super-hard material and having a surface of a prescribed flatness; positioning a glass plate, a thermoplastic resin film, and a stamper containing a track pattern in the mold; and press-molding the glass plate with the track pattern of the stamper at the distortion temperature of glass. The prescribed flatness of the surface is 10 xcexcm or less. The thickness of the thermoplastic resin film is 0.05-0.08 mm.
According to another aspect of the present invention, a glass substrate for an optical disk comprises a track pattern formed in the surface thereof by the above-described method.